A variety of energy management systems have heretofore been suggested. For example, Laid-Open Japanese Patent Application No. 2006-162424 discloses a configuration in which information relating to electricity usage is created based on measurement results of the entire electricity usage in each household (home) or electricity usage at each electric apparatus, and the created information is provided to each household.
In particular, in the energy management system disclosed in the aforementioned Laid-Open Japanese Patent Application, when information relating to the electricity usage is created, the results obtained by measurements in each household are compared with past electricity usage in the households and an average value for an housing complex (for example, mansions and the like) to which the household belongs.
Therefore, in the energy management system disclosed in the aforementioned Laid-Open Japanese Patent Application, it is possible to determine whether the electricity usage at the own household has increased over that in the past and whether the electricity usage is greater than the average value for the housing complex.
However, it is impossible to determine the ranking of the own household in terms of the electricity usage in comparison with other households in the housing complex and the degree to which the electricity usage can be decreased in comparison with that in other households.
Therefore, with the energy management system disclosed in the above-mentioned Laid-Open Japanese Patent Application, it is impossible to stimulate competition in terms of energy saving among the households, and this energy management system is insufficient from the standpoint of increasing the consciousness for energy saving.